Hydraulic machine



' Dec. 7, 1937. E, K E EDEK 2,101,731

HYQRAULIC MACHINE Filed Aug. 31, 1936 5 Sheets-Sheet l Z'Ze/s/ffierzede Dec. 7, 1937. K. BENED'VEK 2,101,731

HYDRAULIC MACHINE Filed Aug. 31, 1936 5 Sheets-Sheet 2 Dec. 7, 1937. E. K. BENEDEK HYDRAULIC lflACI-IINE Filed Aug. 31, 1936 5 Sheets-Sheet 3 Dec. 7, 1937. BENEDEK 2,101,731

HYDRAULIC MACHINE Filed Aug. 51, 1956 5 Sheets-Shet 5 Patented Dec. 7, 1937 UNITED STATES PATENT OFFICE 2,101,131 mnamo monmn Eiek K. Benedek, Bucyi'us, Ohio Application August 31, 1936, Serial No. 98,807 18 Claims (01. 103-161) 'vention disclosed in the aforenamed copending application is the provision of aplurality of rolling load transmitting devices extending through each piston cross-head and engaging the reactance rings, the rolling devices associated with each piston being spaced from each other and so located with reference to the piston axis as to provide for efficient transmission of both torque and thrust efforts. The provision of a plurality of such rolling devices and the use of solid, completely circular reactance rings as disclosed in the copending application necessitate extremely accurate and expensive machining of the parts in order to avoid harmful binding of the parts. I also have found it desirable in some cases to provide machines of the kind disclosed in the copending application with special bearings in order to eliminate binding due to slight inaccuq to provide such improvements in the construction disclosed in the copending application. as will render it less expensive to provide for perfect alignment of the rolling devices with the cooperating roller ways (in the piston cross heads or the reactance member, as the case may be) so as to eliminate danger of binding, and at the same time to provide such an arrangement as will permit the use of standard bearings.

Another object is to provide a construction of the character referred to' in which the reactance member comprises a plurality of self-aligning blocks. each having drive connection with one of the pistons.

A further object is to provide ahydraulic machine of the general character referred to and including means -for transmitting both torque and thrust to or from the pistons with a minimum of loss due to friction and with no harmful bind- .ing, the organization being such as to permit the use of standard machine elements without requiring excessively accurate machining of the parts.

A further object is to provide a pump or motor racies in machining the'unitary reactance rings; One of the objects of the present invention-is of the kind referred to having rolling thrust and torque transmitting means generally similar to the thrust and torque transmitting means disclosed in my copending application, Serial No. 50,671, but differing therefrom in that with structures embodying the present invention, alignment of the piston cross heads and associated reactance means is accomplished more easily and hence more economicallythan with constructions, as disclosed in my copending application. I It will be understood that the foregoing brief statement of objects of the invention is not neces- Figure 2 is a longitudinal sectional view taken a on the line 2-2 of Figure 1;

Figure 3 is a transverse sectional view taken 'on the line 3-3 of Figure 2, the pump casing being omitted;

Figure 4 is a detail view in elevation showing a reactance block element;

Figure 5 is a section taken on the line 5-5 of- Figure 4 showing two block elements in cooperative relation;

Figure 6 is a view in elevation of one form of piston and cross head connected thereto;

Figure 7 is an elevation showing a piston before its connection to the cross head;

Figure 8 shows a cross head before its connection to the piston;

Figure 9 is a longitudinal sectional view of a modified form of pump embodying the invention, the section being taken on the line 9-9 of Figure 10;

Figure 10 is a transverse sectional view taken on the line l0 'l0 of Figure 9;

Figure 11 is a perspective view of a blank from which a unitary combined piston and'cross head may be formed;

Figure 12 is a view partly in section and partly in elevation showing a cross head and rolling pin assembly; and

Figure 13 is a section taken on the line l3-I3 of Figure 12.

One preferred embodiment of the invention as illustrated in Figures 1-8 includes a casing I provided with an end cover 2 and formed with an axial bore 3 for receiving a stationary pintle I.

A cylinderfbarrel I is mounted for rotation about If rounding the pintle are mounted respectively in a the pintle by means of a bearing assembly 6;

the outer race of which is positioned in a bore 1 formed in the barrel, the inner race fitting around the pintle, and a bearing assembly 8 the outer race of which is fitted in a bore 9 formed in the cylinder barrel, and the inner race of which is mounted upon a reduced portion ll] of the pintle. A washer II is drawn up against the inner race of the bearing 8 by means of a nut l2 on the end of the pintle.

Torque is transmitted to or from the cylinder barrel by means of a shaft l3 which is coupled to the cylinder barrel by screws l4, the shaft being formed witha flange l5 which bears against the outer race of the bearing 8 to lock it in place in the bore 9 of the cylinder barrel. Bearings i6 positioned in a bore ll of the end plate 2 mount the shaft it for rotation in the casing.

The cylinder barrel is formed with a plurality of radially disposed cylinders l8 arranged in a common plane. Passages is provide communication between the inner ends of the cylinders and the cylinder barrel bore, and are adapted upon rotation of the cylinder barrel to register with valve ports 20 in the pintle which communicate with pintle passages 2|. As will be well understood by those skilled in the art, rotation of the barrel will cause valving cooperation of the passages it with the pintle ports 20, thereby effecting valved control of flow to and from the cylinders. Pistons 22 arranged in a group surthe cylinders it. Each piston is provided with or has connected thereto a crosshead element 23.

In accordance with the present invention, as in the case of machines of the kind disclosed in my copending application 50,671, there is provided a non-rotary outer reactance ring 24 which, in operation, is disposed eccentrically with respect to the pintle axis. In the form shown, the reactance ring 24 is formed with pads 25 which have sliding engagement with pads 26 on the inside of the casing l, and is adapted to be moved to selected eccentric positions by means of shifting rods 27. Bearing assemblies 28 interposed between the shiftable non-rotatable reactance ring 24 and a rotatable reactance assembly generally designated 29 support the latter for rotation about an axis eccentric with respect to the pintle axis.

In accordance with an important feature of the present invention, the means for transmitting driving force between the pistons and the reactance assembly comprises the cross head elements 23, a plurality of self-aligning thrust block elements 30 fixed in the reactance assembly, and rolling load-transmitting devices or pins H extending through each cross head and engaging the blocks 3| on opposite sides of the respectively associated piston axes. In order to obtain the necessary optimum alignment, the elements which cooperatively engage the pins 3i, namely, the blocks'30, are formed separately, at least one for each piston and cross head, so as to permit the blocks to be aligned individually when the machine is assembled. In the form shown, the

blocks 30 are formed as segments of a circle and are assembled in a generally circular arrangement. To permit slight shifting of the blocks for aligning purposes, a, substantial clearance space 32 is provided between the contiguous ends of adjacent blocks. The spaces 32 permit movement of the blocks backwards or forwards around the assembly circle during assembly. Preferably the blocks are held in assembled relation by means of cheek-plates 33 formed with seats 34 which receive the blocks somewhat loosely in order to permit each block to shift slightly in assembling for aligning purposes. It will beobserved that, in the illustrated embodiment, the blocks are arranged in pairs, that is, there are two blocks for each cylinder spaced from each other. and each being seated in one of the two spaced cheek plates. The correct spacing of the blocks and the cheek plates is accomplished by means of spacing sleeves 35, see particularly Figure 2, these sleeves fitting between the inwardly directed faces of each pair of blocks. Clamping screws or bolts 36 pass through the cheek plates, the blocks, and the spacing sleeves 35, andwhen drawn tight lock the blocks, the cheek plates, and the sleeves in tight assembled relation. Semicircular clearance spaces or recesses 35 are formed in the ends of the blocks to fit around the clamping screws 36 without contacting the latter, thereby permitting the necessary shifting of the blocks to produce correct alignment during assembly.

The blocks 30 are formed with ways 31 extending normal to the piston axes and having inner and outer working surfaces upon both of which the pins 3! are adapted to roll.- Preferably, the pins are journaled in the cross heads 23 by means of anti-friction rollers such as capillary needle bearings 38. These bearings comprise a plurality of rolling elements the length of which is greater with respect to the diameter than the conventional roller bearings whereby capillary oil spaces are provided between contiguous rollers. The

total clearance between the individual rolling.

elements of each needle bearing set 38 should amount to about the diameter of one rolling element or a little less. Figures 12 and 13 show in more detail the mounting of the pins 3| by means of the needle bearings. The rollers 38 are shown as being held in place by retaining washers 39 having a press fit on the pins 3!. If

desired, a bushing 40 may be inserted in the cross head 30 for receiving the needle bearings and washers.

In order to maintain the bearings 38, the pins 3|, and the ways 3l fiooded with lubricating and cooling fluid, I provide an oil-retaining ring or drum 4! which surrounds the blocks 30 and spans the gap between the outer edges of the cheek plates, the drum ll blocking or damming the flow of slip fluid, i. e., fluid WhiC'l leaks past the pistons during high pressure operation and is thrown by centrifugal force into the ways 31.

It will be understood that when assembling a machine of the kind described the individual blocks 30 will align themselveswith respect to the associated pistons so that the way 31 in each block will be normal to. the axis of the associated piston. Such alignment is essential to successful and efficient operation, since the spacing of the pins 3| on opposite sides of the piston axis and the close fit of the pins in the ways 31 would result in binding of the pins in the working surfaces of the ways if there should be the slighest sired alignment has been obtained in the manner set forth above, the screws 36 are tightened so as to clamp the blocks 30 between the cheek plates 33, the blocks 30 of course being spaced from each other by means of the sleeves 35. The cheek plates 33 and the blocks 30 will then form a .rigid solid reactance member. v

The importance of providing extremely accurate alignment will be apparent when it is considered that, if there should be even a temporary binding or seizure preventing the pins 3i from rolling and making it necessary for them to slide on the ways 31, the pins would wear flat. Once even a small flat surface is worn on a pin, it is never able to roll thereafter. Moreover, the machine actually could not operate with the pins sliding in the ways because the concentrated load on the substantially line-bearing contact almost immediately would create such localized high temperature that there would be danger of fire.

The disposition of the pins 3i on opposite sides of the respectively associated piston axes provides for efficient transmission of torque and thrust forces without danger of seizure and without any tendency for the rollers 3i to dig into the working surfaces of the ways 31. Thus, among other advantages of constructions embodying the present invention, there is the advantage of the efficient torque and thrust transmission obtain-ed also.with machines as disclosed in my copending application 50,671, but in the present case the construction is less expensive than that disclosed in the copending application, and moreover makes it possible to employ even smaller clearances, so that noise and wear are reduced materially.

It will be'observed that each cross head element 23 and its associated block element or elements 30 constitute a driving pair, one of the elements of the pair being formed with a way 31 extending substantially normal to the associated blocks and the pins are journaled in the'cross heads, is merely one form shown for the purposes of illustration.

In order to dispense with non-ferrous bushings and other bearing surfaces, I prefer to employ hardened steel bearing parts throughout. It is possible to employ steel-on-steel bearings in constructions embodying the present invention because of the perfect alignmentgof the parts made possible by the use of the self-aligning thrust blocks 30 and because of the disposition of the pins 3i on opposite sides of the piston axes so as to transmit the torque without seizure and binding. It is, however, desirable that the steel .bearing surfaces be very hard, and to this end I may employ accurately machined hardenedground and polished elements. I may employv nitro-alloy, in which case, after finished machining,the element will be nitrided at about 750 F. for ninety hours. Alternatively, parts may be. chromium plated, particularly the cyl- This arrangement broadly set forth above inder barrel and cylinders.

or other element containing nickel and chromium by means of electrolysis. The chromium plate should be applied to such thickness as to permit a finish grinding of the parts after plating has been completed. The use of chromium plating has the advantage also of providing a way for repairing parts which are worn small after long use in severe service so as to restore the parts to their original size and eliminate clearance and play developed during wear. This is particularly' useful in reconditioning cylinders and pistons so as to reduce slip.

Figures 6, 7, and 8 show a form of piston and cross head assembly well adapted for use in machines embodying the present invention and inexpensive to produce. This assembly includes a cylindrical piston 43 shown in Figure 7 which may be cut from round bar stock and a platelike cross head 44 which may be cut from plate stock. The cylinder element 43 has one end chamfered as at 45 and is placed in abutting relation to the cross head plate 44 as shown in Figure 6. With the parts held in the relative position shown in Figure 6, they are welded by a ring of welding metal as indicated in Figure 7 by any suitable welding process. form of combined piston and cross head may be made from a one-piece blank as shown in Figure 11. The cross head portion 48 thereof will be machined to substantially the same shape as the cross head portion 44 shown in Figure 8, whereas the piston portion 49 of the blank shown in Figure 11 will be turned to the cylindrical shape of the element 43 shown in Figure 7. Whatever form of piston and cross head is employed, it is important that the radial sides of the cross head be ground accurately so as to fit snugly between the thrust blocks 30. Although no load is transmitted from the radial faces of the cross heads to the thrust blocks or vice versa,

it is important that the parts fit nicely and be smooth so as to avoid frictional losses and binding.

'50 including two setsof rollers and races, the

outer races 5i being tapered off at the ends of the rolling surfaces so as to permit relative axial movement between the rollers and the outer races. Similar roller bearing assemblies 52 having outer races 53 are interposed between the opposite end of the cylinder barrel and the reduced portion ll) of the pintle. The arrangement is such as to permit slight relative axial movement of the cylinder barrel with respect to the pintle in order to permit expansion due to heating. The shaft 13 is supported for rotation in the casing by means of two ball bearing assemblies generally designated 54.

The load-transmitting means shown in Figures 9 and 10 differs from that shown in Figures 1 and 2 in that-for each piston and crbss head three rollers are provided. One roller 5i has its An alternative The chromium plat- 'ing maybe applied to a cast iron cylinder barrel axis intersecting the piston axis, whereas the other two rollers 3| are spaced on opposite sides 01. the piston axis, as are the rollers 3i in the form shown in Figures 1 and 2. Thethree-roller arrangement shown in Figures 9 and 1!) possesses the advantage that the central roller 55 associated with each piston is so positioned as to transmit the piston thrust directly to the blocks 30so as to avoid any beam deflection effect in the cross head due to transmission of thrust forces outwardly to the rollers 3i. The rollers 3|, however, being spaced on opposite sides of the piston, axis, function efficiently to. transmittorque.

In the foregoing description, reference has been made to pumps, but it will be understood that theconstruct'ions disclosed are adapted for operation either as pumps or as hydraulic motors. The constructions disclosed embody the invenl'orm, but'it will be understood that changes may be made in the specific construction and relative arrangement of the parts without departing from the invention as defined in the claims.

I claim:

1. In a hydraulic machine of the class described; a rotatable group of radial cylinders and cooperating pistons; a rotatable reactance assembly surrounding said piston group; and means for and the reactance assembly, said means comprising a plurality of cross head elements, one connected to each piston, a plurality of separate selfaligning block elements fixed in said reactance assembly, there being at least one block element associated with each cross head element, each cross head element and its associated block element constituting a driving pair and one of the elements of each pair being formed with a way extending substantially normal to the associated piston axis and in a plane normal to the axis of rotation of the piston group, said ways each have -ing inner and outer working surfaces, and rolling load-transmitting means operatively engaging both elements of each pair and extending through each cross head element on opposite sides of the associated piston axis and being adapted to have rolling engagement with the inner and outer working surfaces of the associated way.

2. In a hydraulic machine of the class described; a rotatable group of radial cylinders and cooperating pistons; a rotatable reactance assembly surrounding said piston group; and. means for transmitting driving force between the pistons. and the reactance assembly, said means comprising a plurality of cross head elements, one connected to each piston, a plurality oi. sep arate self-aligning block elements fixed in said reactance assembly, there being at least one block element associated with each cross head element, each cross head-element and its associated block element constituting a driving pair and one 01 the elements of each pair being formed with a way extending substantially normal to the associated piston axis and in a plane normal to the axis of, rotation of the'piston group, said ways each having inner and outer working surfaces, and rolling load-transmitting means operatively engaging both elements of each pair and extending through each cross head element on opposite sides ofi-the'associated piston axis, the loadtransmitting driving force between the'pistons.

tion in practical and the at present preferred 1 way in one element of the pair and being journalled for rotation in the other element of said pair.

3. In a hydraulic machine of the class described; a rotatable group of radial cylinders and cooperating pistons; a rotatable reactance assembly surrounding said piston group} and means for transmitting driving force between the pistons and the reactance assembly, said means comprising a plurality of. cross head elements, one connected to each piston, a plurality of. separate self-aligning block elements fixed in said reactance assembly, there being at least one block element associated with each cross head element, each cross head element and its associated block element constituting a driving pair and one of the elements of each pair being element on opposite sides 01' the associated pistransmitting means associated with each driving, pair being adapted to have rolling engagement 5 with the inner and outer working surfaces of the ton axis, the load-transmitting means associated with each driving pair being adapted to have rolling engagement with the inner and outer working surfaces of the way in one element of. the pair, and capillary needle bearings journaiiing said means for rotation in the other element oi said pair.

4. In ahydraulic machine of the class described; a rotatable group of radial cylinders and cooperating pistons; a rotatable reactance assembly surrounding said piston group; and means for transmitting driving force between the pistons and the reactancev assembly, said means comprising a plurality of cross head elements, one connected to each piston, a plurality of separate sell-aligning block elements fixed in said reactance assembly, there being at least one block element associated with each cross head element, each block being formed with a way extending substantially normal to the associated piston axis and in a plane normal to the axis of rotation of the piston group, said ways each having inner and outer working surfaces, and rolling load transmitting means operatively engaging said cross head elements and the respectively associated block elements on opposite sides or the associated piston axes and being adapted to have rolling engagement with the inner and outer working surfaces of the respectively associated ways. I

5. In a hydraulic machine of the class described; a rotatable group of radial cylinders and cooperating pistons; a rotatable reactance assembly surrounding said piston group; and means for transmitting driving force between the pistons and the reactance assembly, said'means comprising a plurality of cross head elements, one connected to each piston, a plurality 01 separate self-aligning" block elements fixed in said reactance assembly, there, being at least oneblock element associated withJeach cross way extending substantially normal to the assoiciated piston axis and in a plane normal to the axis or rotationof the'piston group,- said'ways' each having inner and outer working surfaces,

and rolling load transmit ing means operatively" engaging said cross head elements and; therepectively associated block elements onomg 4 sides oi the associatedfipiston axcasald loadtransmitting means being journalled for rotation in said cross head elements and being adapted to have rolling engagement with the inner and outer working surfaces of the respectively associated ways.

6. In a hydraulic machine of the class described; a rotatable group of radial cylinders and cooperating pistons; a rotatable reactance assembly surrounding said piston group; and means for transmitting driving force between the pistons and the reactance assembly, said means comprising a plurality of cross head elements, one connected to each piston, a. plurality of separate self-aligning block elements fixed in ,said reactance assembly, there being at least one block element associated with each cross head element, each blockbeing formed with a way extending substantially normal to'the associated piston axis and in a plane normal to the axis of rotation of the piston group, said ways each having inner and outer working surfaces, rolling load-transmitting means operatively engagated with each cross head element being disposed on opposite sides of the cross head element and each block element being operatively e g d by the rolling load transmitting means which engages the associated cross head element.

8. In a machine of the class described, the

combination defined in claim 2 and in which two blockelements are associated with each cross head element, the block elements associated with each cross head element being disposed on opposite sides of the cross head element and each block element being operatively engaged by the rolling load transmitting means which engages the associated cross head element.

9. In a machine of the class described, the combination defined in claim 3 and in which two block elements are associated with each cross head element, the block elements associated with each cross head element being disposed on opposite sides of the cross head element and each block element being operatively engaged by the rolling load-transmitting means which engages the associated cross head element.

10. In a machine of the class described, the combination defined in claim 4 and in which 'two block elements are associated with each .rollingload-transn'iitting means which engages the associated cross head element.

12. In a machine of the class described, the combination defined in claim 6 and inwhich two block elements are associated with each cross head element, the block elements associated with each cross head element being disposed on opposite sides of the cross head element and each 'block element being operatively engaged by the rolling load-transmitting means which engages the associated cross head element.

13. In a hydraulic machine of the class described; a rotatable group of radial cylinders and cooperating pistons, a plurality of cross head elements, one connected to each piston; a rotatable reactance assembly surrounding said piston group and including a plurality of separate self-aligning block elements, at least one associated with each cross head element, cheek plates respectively on opposite sides of the block elements, and means for drawing the cheek plates together to clamp the reactance blocks therebetween, each cross head element and its associated block element constituting a driving pair and one of the elements of each pair being formed with a'way extending substantially normal to the associated piston axis and in a plane normal to the axis of rotation of the piston group, said ways each having inner and outer working surfaces, and rolling load-transmitting means operatively engaging both elements of each pair and extending through each cross head element on opposite sides of the associatedpiston axis and being adapted to have rolling engagement with the inner and outer working surfaces of the associated way.

14. In a hydraulic machine of the class described; a rotatable group of radial cylinders and cooperating pistons, a plurality of cross head elements, one connected to each piston; a rotatable reactance assembly surrounding said piston group and including a plurality of separate self-aligning block elements, at least one associated with each cross head element, cheek plates respectively on opposite sides of the block elements, said end plates being formed with seats for receiving said block elements in substantially aligned positions but there being sufiicient clearance between said seats and the block elements to permit movement of the blocks within the seats for self-alignment of the blocks, and means fordrawing the cheek plates together to clamp the reactance blocks therebetween, each cross head element and its associated block element constituting a driving pair and one of the elements of each pair being formed with a way extending substantially normal to the associated piston axis and in a plane normal to the axis of rotation of the piston group,

said ways each having inner and outer working surfaces, and rolling load-transmitting means operatively engaging both elements of each pair and extending through each cross head element on opposite sides of the associated piston axis and being adapted to have rolling engagement with the inner and outer working surfaces of the associated way.

15. In a hydraulic machine of the class described; arotatable group of radial cylinders and cooperating pistons; a rotatable reactance assembly surrounding said piston group; and means for transmitting driving force between the pistons '10 and the reactance assembly, said means compris-J ance assembly, there being at least one block element associated with each cross head element, each cross head element and its associated block element constituting a driving pair and one of the elements of each pair being iormed with a way extending substantially normal to the associated piston axis and in a plane normal to the axis of rotation of the piston group, said ways each having inner andouterworking surfaces. and two cylindrical rolling devices operatively engaging both elements of each pair andextending through each cross head element respectively on opposite sides of the associated piston axis and being adapted to have rolling engagement with the inner and outer working surfaces of the associated way.

l6.In a machine oi the class described, the combination defined in claim 15 and in which two block elements are associated with each cross head element, the block elements associated with cooperating pistons; a rotatable reactance assembly surrounding said piston group; and means for transmitting driving force between the pistons and the, reactance assembly, said means comprising a plurality of cross head elements, one connected to each piston, a plurality of separate self-aligning block elements fixed in said reactance assembly, there being at least one block element associated with each cross head element, each cross head element and its associated block element constituting a driving pair and one of the elements 015188-011 pair being formed with a way extending substantially normal to the associated piston axis and in a plane normal to the axis of rotation of the piston group, said ways each having inner and outer working surfaces, and three cylindrical rolling devices operatively engaging both elements 01 each pair and having their axes parallel to the axis of rotation of said piston group, the axis of one of said rolling devices intersecting the associated piston axis'and the axes of the other two rolling devices being spaced respectively on opposite sides of the associated piston axis, all three of said rolling devices being adapted to have rolling engagement with the inner and outer working surfaces of the associated way.

18. In a machine of the class described, the combination defined in claim 17 and in which two block elements are associated with each cross head element, the block elements associated with each cross head element being disposed on opposite sides of the cross head element and each block element being operatively engaged by the rolling devices which engage the associated cross head element.

. ELEK K. BENEDEK. 

